Fix editLoaded computation

A recent change moved the mechanism for managing the selected patchsets
from within the `patchRange` property to two individually managed
properties. This change updates `_computeEditLoaded` to reflect that.

The `_editLoaded` property depends only on `_patchNum`.

Change-Id: Ia8863902692dac007376904dbc75270d2f834e50
diff --git a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.js b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.js
index e143cc1..fd20e44 100644
--- a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.js
+++ b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.js
@@ -197,7 +197,7 @@
       _sortedRevisions: Array,
       _editLoaded: {
         type: Boolean,
-        computed: '_computeEditLoaded(_patchRange.*)',
+        computed: '_computeEditLoaded(_patchNum)',
       },
     },
 
@@ -1287,9 +1287,8 @@
       return change.work_in_progress ? 'header wip' : 'header';
     },
 
-    _computeEditLoaded(patchRangeRecord) {
-      const patchRange = patchRangeRecord.base || {};
-      return this.patchNumEquals(patchRange.patchNum, this.EDIT_NAME);
+    _computeEditLoaded(patchNum) {
+      return this.patchNumEquals(patchNum, this.EDIT_NAME);
     },
   });
 })();
diff --git a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_test.html b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_test.html
index ec32991..27e2262 100644
--- a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_test.html
+++ b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_test.html
@@ -1149,11 +1149,9 @@
     });
 
     test('_computeEditLoaded', () => {
-      const callCompute = range => element._computeEditLoaded({base: range});
-      assert.isFalse(callCompute({}));
-      assert.isFalse(callCompute({basePatchNum: 'PARENT', patchNum: 1}));
-      assert.isFalse(callCompute({basePatchNum: 'edit', patchNum: 1}));
-      assert.isTrue(callCompute({basePatchNum: 1, patchNum: 'edit'}));
+      assert.isFalse(element._computeEditLoaded(1));
+      assert.isFalse(element._computeEditLoaded(''));
+      assert.isTrue(element._computeEditLoaded(element.EDIT_NAME));
     });
 
     test('_processEdit', () => {